Hyaluronic Acid Molecular Weight: Why It Matters

Hyaluronic acid is everywhere in skincare, but you may have seen products mention different molecular weights. Here is what that actually means.

What molecular weight means

Hyaluronic acid comes in different sizes, described as molecular weights. The size affects how the molecule behaves on and within the skin.

What the research found

A study in Skin Research and Technology used Raman spectroscopy to follow how hyaluronic acid of different molecular weights penetrated human skin, finding that penetration depth depended on the molecular weight (Essendoubi et al., 2016, PMID 25877232). In practical terms, lower molecular weight hyaluronic acid tends to travel further into the upper skin, while higher molecular weight forms tend to sit nearer the surface and hold water there.

Why formulas combine sizes

• Many serums use a blend of molecular weights for hydration at different levels.
• Hyaluronic acid is a humectant, so applying it to slightly damp skin and sealing with a moisturiser helps.
• In very dry air, layering a cream on top prevents the hydration from evaporating.

At Verdo we stock the Medik8 Hydr8 B5, a hyaluronic acid and vitamin B5 serum, and the Medik8 Total Moisture cream to seal it in.

Disclaimer: This article is for general information only and is not medical advice. The studies cited are from peer-reviewed journals and are provided for educational context. Individual results vary. Speak with a qualified healthcare professional or dermatologist before changing your routine. Verdo Cosmetics makes no therapeutic claims about the products or services mentioned.